Atrial fibrillation (AF) is the leading cause of hospitalization due to cardial arrhythmia. Current treatments for AF include pharmacological treatments, and surgical treatments such as catheter ablation, with or without using implantable devices, and pace makers.
Over the last decades, various cardiac ablation technologies and procedures have been developed for patients with drug-resistant cardiac arrhythmias. It is now widely accepted that in selected patient populations, catheter ablation is an advantageous alternative to lifelong pharmacologic treatment (Oral et al. Circulation 2003; 108:2355-2360; Morady et al., New England Journal of Medicine 1984; 310:705-707; Calkins et al., Europace 2007; 9:335). Ablation consists of delivering physical energy locally to specific myocardial regions so as to interrupt the pathway of electrical circuits perpetuating the arrhythmia. Regardless of the energy employed, radiofrequency, ultrasound or other, ablation techniques are severely limited by the non-specific nature of the resultant cellular damage. As an example, bystander cells such as fibroblasts, adipocytes or neurons, experience similar damage to myocytes perpetuating the arrhythmia, resulting in post-ablation complications such as cardiac perforation, atrioesophageal fistula, pulmonary veins stenosis, bleeding, coronary spasm or stroke (Cappato et al., Circulation 2005 Mar. 8, 2005; 111:1100-1105; Pappone et al., Circulation 2004 Jun. 8, 2004; 109:2724-2726; Sosa et al., J Cardiovasc Electrophysiol 2005 March 2005; 16:249-250; Robbins et al., Circulation 1998; 98:1769-1775). Besides, this lack of cellular discrimination markedly increases the required energy amounts and prolongs procedure times, all of which reduces overall ablation efficacy. For instance, about 50% of patients undergoing catheter ablation for persistent atrial fibrillation (AF) will experience an arrhythmia recurrence which will require a redo procedure (Weerasooriya et al., Journal of the American College of Cardiology 2011; 57:160-166). Also, trans-mural lesions in specific regions of the heart, such as the mitral isthmus of the left atrium, are difficult to achieve with radio frequency technology, and incomplete lesions may set the stage for arrhythmia recurrence (Sawhney et al., Circulation: Arrhythmia and Electrophysiology 2011).
Improved methods of ablation to treat disorders such as AF are needed.